Yeah, well I guess so, except that when they can no longer close, they die.
Therefore, it sort of ceases to matter.
 
By "swept under the rug" I meant that they occur, are sometimes reported but
disbelieved and dismissed as probably due to measurement errors.  Sometimes
this is justified by saying that negative shell growth is impossible in
bivalves (it is not).
 
The pH 7-8 range was mentioned because it is the norm for lakes. These are
not acid lakes, for example.  Lakes are usually circumneutral unless
acidified, very poor in alkalinity, or full of DOC.
 
Shell loss in living bivalves is extremely common in freshwaters and I'll
bet it is in marine systems, too.
 
 
                        John
 
 
At 09:12 PM 3/26/98 -0500, you wrote:
>Sorry.  I mistyped that last message.  I meant to say that shell loss
>creates failure of closure to limit the problems of tight closure.
>